The present invention relates generally to syringes for use with injectors and to methods of manufacturing syringes and other devices and, particularly, to syringes manufactured by blow molding and to methods of blow molding syringes and other devices.
In many medical procedures, such as drug delivery, it is desirable to inject a fluid into a patient. Likewise, numerous types of contrast media (often referred to simply as contrast) are injected into a patient for many diagnostic and therapeutic procedures for example, gene therapy, cell and biological agent delivery, and delivery of therapeutic agents generally). For example, contrast media are used in diagnostic procedures such as X-ray procedures (including, for example, angiography, venography, urography,), computed tomography (CT) scanning, magnetic resonance imaging (MRI), and ultrasonic imaging. Contrast media are also used during therapeutic procedures, including, for example, angioplasty and other interventional radiological procedures.
A number of injector-actuated syringes and powered injectors for use in medical procedures such as angiography, computed tomography (CT), ultrasound and NMR/MRI have been developed. A front-loading syringe and injector system is, for example, disclosed in U.S. Pat. No. 5,383,858, assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. Other front-loading syringes and injectors systems are, for example, disclosed in U.S. Pat. No. 6,652,489, the disclosures of which are incorporated herein by reference.
Historically, it has been difficult to manufacture syringes with desirable transparent optical properties that exhibit sufficient strength for use with front-loading, pressure jacketless injectors. Indeed, depending upon the application, syringe pressures in the range of 300 psi to 1200 psi are commonly experienced in injection procedures using powered injectors. Typically, to achieve suitable strength, the syringe walls must be thickened during manufacture, which increases costs and, depending upon the material, can degrade optical properties. However, in the current injection molding practices for manufacturing syringe, there is a limit to the wall thickness that can be achieved. This limit can result in syringes designed with a lower safety factor than desirable. Moreover, as wall thickness is increased, production costs also increase. For example, increases in wall thickness are associated with longer injection times, longer packing times, higher pressures, longer cooling time, and increased resin costs.
It is desirable to develop new syringes and methods of fabricating or manufacturing syringes that reduce or eliminate the above-identified and other problems associated with current syringes and methods of manufacture.